Alternation (Language)

Glossary of grammatical and rhetorical terms

A cat and a dog sitting across from each other at a table
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In linguistics, alternation is a variation in the form and/or sound of a word or word part. (Alternation is equivalent to allomorphy in morphology.) Also known as alternance.

A form involved in an alternation is called an alternant. The customary symbol for alternation is ~.

American linguist Leonard Bloomfield defined an automatic alternation as one that's "determined by the phonemes of the accompanying forms" ("A Set of Postulates for the Science of Language," 1926). An alternation that affects only some morphemes of a particular phonological form is called non-automatic or non-recurrent alternation.

Before we get to examples of alternations, here are other terms that are often confused with alternation, but actually have different meanings:

Spelling and Sounds

"Certain English nouns ending in the consonant /f/ form their plurals with /v/ instead: leaf but leaves, knife but knives. We say that such items exhibit an /f/-/v/ alternation. . .

"A somewhat different alternation is found in related words like electric (which ends in /k/) and electricity (which has /s/ instead of /k/ in the same position).

"More subtle is the three-way alternation occurring in the English plural marker. The noun cat has plural cats, pronounced with /s/, but dog has plural dogs, pronounced with /z/ (though again the spelling fails to show this), and fox has plural foxes, with /z/ preceded by an extra vowel. This alternation is regular and predictable; the choice among the three alternants (as they are called) is determined by the nature of the preceding sound."
(R.L. Trask, Language and Linguistics: The Key Concepts, 2nd ed., ed. by Peter Stockwell. Routledge, 2007)

From Phonology to Morphology

"[T]ypically, an allomorphic alternation makes the most sense phonologically if one looks at an earlier stage of the language. Here are [five] striking examples:

foot feet
goose geese
tooth teeth
man men
mouse mice

In this list of words, the different vowels in the plural arose in Prehistoric English. At that time, the plurals had an /i/ ending. English also had a phonological rule (known by the German word umlaut) whereby vowels preceding an /i/ became closer to the /i/ in pronunciation. At a later date, the ending was lost. In terms of the phonology of Modern English, the current allomorphy is doubly senseless. First, there is no overt ending to explain the alternation in the stem. Second, even if there were, English has lost the umlaut rule. For example, we feel no pressure at all to turn Ann into xEnny when we add the suffix -y/i/.

"Thus one big source of English allomorphy is the phonology of English. When English loses the phonological rule, or when conditions in the word change so that the rule no longer applies, the alternation often remains in place, and from then on it is a rule of the morphology."
(Keith Denning, Brett Kessler, and William R. Leben, English Vocabulary Elements, 2nd ed. Oxford University Press, 2007)

Alternation and Voice

"The grammatical category of voice affords speakers some flexibility in viewing thematic roles. Many languages allow an opposition between active voice and passive voice. We can compare for example the English sentences in 6.90 below:

6.90a. Billy groomed the horses.
6.90b. The horses were groomed by Billy.

In the active sentence 6.90a Billy, the agent, is the subject and the horses, the patient, is the object. The passive version 6.90b, however, has the patient as the subject and the agent occurring in a prepositional phrase ... This is a typical active-passive voice alternation: the passive sentence has a verb in a different form — the past participle with the auxiliary verb be--and it allows the speaker a different perspective on the situation described."
(John I. Saeed, Semantics, 3rd ed. Wiley-Blackwell, 2009)

Alternation and Predicative Constructions

"According to Langacker (1987: 218), predicative adjectives have a relational profile: they convey a quality, which functions as the landmark (lm) in the reduction, that is associated with the entity denoted by the subject of the utterance, which is the trajector (tr). Consequently, only elements with a relational profile can be used as predicates. Applied to the discussion of grounding elements, this entails that alternation with a predicative construction is only available for elements that express deictic meanings but profile the grounding relation, e.g. a known criminal - a criminal that is known, and not for grounding predications, which have a nominal profile. As shown in (5.28), comparative determiner units do not allow alternation with the predicative construction, which suggests them to have a nominal rather than a relational profile:

the same man ⇒ *a man that is the same
another man ⇒ *a man that is another
the other man ⇒ *a man that is the other"

(Tine Breban, English Adjectives of Comparison: Lexical and Grammaticalized Uses. Walter de Gruyter, 2010)

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Nordquist, Richard. "Alternation (Language)." ThoughtCo, Aug. 26, 2020, Nordquist, Richard. (2020, August 26). Alternation (Language). Retrieved from Nordquist, Richard. "Alternation (Language)." ThoughtCo. (accessed June 9, 2023).